1. Field of the Invention
The present invention relates to a method for treating a fluid.
2. Description of Related Art Including Information Disclosed Under 37 C.F.R. 197 and 37 C.F.R. 1.98
The treatment of fluids, regardless whether for purification or enrichment for instance, may be realized by different techniques according to the scale at which it is desirable to work.
Separation membranes are used generally for applications on significant volumes of fluid, but this system is not satisfactory since the selectivity and/or the speed of transport remains limited. Besides, an application to samples of microscopic volume remains risky.
One of the ideal methods for separating biological molecules is gel electrophoresis (based upon differential transport of polyelectrolytes such as DNA or proteins). Gels having small-sized pores may be realized reproducingly. The latter, in addition to restricted lifetime, exhibit the shortcoming of possessing pores whereof spatial distribution remains aleatory. Finally, this technique remains slow and hardly automatable since efficient gels cannot be prepared beforehand.
The use of three-dimensional networks has been extended through the study of polymers. However, although numerous type of zeolite or nanoporous polymers have been developed, the developed surface of such systems still remains limited, and accessibility to the pores is restricted. The chemical composition of such systems is, moreover, relatively reduced (“adaptability” of the pores) and the reactivity of certain metallic salts may be an additional risk factor during purification.
One of the possible alternatives to these methods rests with the realization of “artificially” nanostructured networks having regular geometry, flexible and controllable so as to adapt the structures to various targets molecules. The available nanostructuring techniques (“top-down” approach) are however cumbersome to implement (since X-ray, electron or ion lithography usually requires white room working) [J. Fu, Applied Physics Letters, 2005, 87, 263902]. The production times are long and the costs are high.
Besides, and in spite of the recent development of techniques such as “nanoimprinting” (transfer of structures by means of pads), large-scale production of such regular structures remains problematic.
Until now, nanostructuring techniques have only enabled to obtain structures greater than a few ten nanometers. However, the needs to handle wide varieties of molecules of various size and shape require implementing fully new approach also compatible with large scale production imperatives. Consequently, so-called “bottom-up” technologies, using in particular self-assembly of molecules exhibits an interesting alternative.
However no method has truly enabled to provide confluence of the “top-down” and “bottom-up” techniques, nanoscopic structures of molecular size (1-10 nm) are hence required enabling to control selectively and rapidly the movement of individual molecules (selective transport) [D. Mijatovic, Lab on a Chip, 2005, 5, 492-500].
The aim of the present invention is to provide a method for treating a fluid, which remedies the shortcomings aforementioned, in particular as regards the passing speed of the fluid.
Another aim of the present invention is to provide a method for treating a fluid, which exhibits better fluid selectivity.
Other aims and advantages of the invention will appear in the following description, which is given solely for illustrative purposes and without being limited thereto.